The present invention relates to a magneto-optical disk drive system, and more particularly to a position adjusting assembly for positionally adjusting magnetic and optical heads with respect to each other across a magneto-optical disk in a magneto-optical disk drive system.
Magneto-optical disk drive systems are capable of rewriting desired information many times on erasable magneto-optical disks. In such a magneto-optical disk drive system, a laser beam of large power, emitted from an optical head, is continuously applied to the recording layer on one surface of a loaded magneto-optical disk to heat small spots or bits on the magnet-optical disk to the Curie point. Then, a biasing magnetic field is applied to the spots by a biasing magnetic field generator or magnetic head to magnetically align the spots in an initial direction. Thereafter, the biasing magnetic field is reversed and a laser beam of large power is intermittently applied through the other surface of the magneto-optical disk to magnetically realign the spots, thus recording information.
The process of rewriting a track of information on a magneto-optical disk is relatively slow, because it is necessary to rotate the magneto-optical disk in both erasing and recording cycles. To eliminate this drawback, there has recently been proposed a magnetic-field-modulated overwrite magneto-optical disk drive system which selectively applies an N or S magnetic field to small spots on a magneto-optical disk where a laser beam is to be converged. The proposed magnetic-field-modulated overwrite magneto-optical disk drive system can rewrite one track of information on the magneto-optical disk simply by rotating the magneto-optical disk only once.
Quick overwriting on the magneto-optical disk requires that a magnetic field, modulated at high speed, be applied to the magneto-optical disk, and a small-size magnetic head be positioned very closely to the recording layer of tile magneto-optical disk. It is also necessary that the magnetic head over one surface of the magneto-optical disk be moved in unison with the optical head that is disposed over the other surface of the magneto-optical disk. To meet such a requirement, the magnetic and optical heads should be positioned in alignment with each other for applying the magnetic field and the laser beam, respectively, positionally accurately to the recording layer of the magneto-optical disk.
There is a need for a magneto-optical disk drive system having a structure that allows a magnetic head over one surface of a magneto-optical disk and an optical head over the other surface thereof to be positionally aligned with each other with ease and accuracy when the magneto-optical disk drive system is manufactured or serviced.